Impulse operated relay



, 1937. D. G. c. LUCK IMULSE OPERATED RELAY Sepa.; 14

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[Zwcrz/for Educ-665% Patented Sept. 14,` 1937 PATENT 1 ortica IMPULSE OPERATED RELAY novia G. c. Look, Woodbury', N. J., mignonto Radio Corporation oi* America, a corporation of Delaware Application ootobor 81, 1935, sonal No. 41,675

9 Claims. (Cl. Z50-27) My invention relates to impulse operated re. lays. Speciiically, my invention is a gastube relay and circuit therefor for alternately starting and stopping current ow by, or for indicat- 5 ing every nth one of, a series of voltage pulses.

I am aware of the-so-called relaxation oscillator Whose output circuit is usually comprised of capacitance and resistance. The time constant, which is' the product of the capacitance,-

l times the resistance, determines the frequency of a series of yoltageimpulses. These impulses are generally of a saw-tooth wave form. I have found certain critical, and heretofore unknown, relations between the voltage and the current in l a gas tube relay which may be used to generate currents of several useful wave forms.

` One of the objects oi my invention is to generate a series of duration-modulated dots or dashes of current which are started and stopped by a series of variably timed identical voltage impulses.

Another object of my invention is to devise means for indicating every nth impulse of a series of voltage impulses.

2.5 Additional objects will be apparent from a consideration of the accompanying speciiications and appended claims.

My invention'may be best understood by refer-v ence to the accompanying drawing in fwhich '3 Figure I is a schematic diagram of one embodiment of my invention,

Fig. ILcomprising curves 11a, IIb, IIe, and rid.'

is an illustration which shows graphically the operation of Fig. I,

Fig. III is a circuit diagram of an embodiment of my invention which may be used to indicate every nth impulse of a series of voltage impulses, and

Fig. IV is an illustration of the plate voltage and plate current characteristics Aof one oi.' the tubes used in Fig. III.

In Fig. I a pair of terminals I, 3, represent the input to the network. lOne of these terminals I 45 is serially connected through a capacitor 5 to the grid-electrode I of a gasfllled relay tube 9. 'I'his tube may be an RCA type 885, or the like. The lament of cathode II is heated by-a suitable source of current. The heating battery -is 5'0 omitted for simplicity. The cathode II is connected to the remaining input terminal 3 lthrough a self-biasing and protective resistor I3. A biasing battery I 4 may be used in addition to the self bias. The grid 1 is connected through 55 the biasing battery I4 tothe input terminal 3 by vthis region, one impulse may be applied to the the anode resistor 2I.-

'a grid resistor I5. The plate I1 is connected. through a capacitor I9 to the lower terminal of` the bias resistor I3. 'I'he plate is also connected through an adjustable resistor 2| to the positive terminal of a B battery 23. 'Ihe negative ter- 5 minal of lthe B battery is connected to the lower terminal of the, bias resistor I3.

The output from the iirst tube 9 is taken across the bias resistor I3, which is connected toJ a second tube 25. This second tube mayTb any con- 10 ventional tube, such as an RCA 56. e cathode 2l of the second tube is heated by a-battery, or :the like. This cathode 21 is connected to the cathode II of the rst tube. The grid 2,9 is connected through a biasing battery 30 to the nega- 15 tive terminal of the B battery 23. The plate 3| is connected through a resistor 33 tothe positive terminal of the B battery.V The plate is also connected through a capacitor.35' to one of a pair of output terminals 31-39.1 The other out- 20 put terminal 39 is connected to the negative terminal of the B battery. The operation of this circuit may be described as follows: If 'a series of voltage impulses are applied to the input circuit oi a gas tube. the tube may operate with a steady discharge, or an oscillatory discharge of a sawtooth pattern occurring at impulse frequency or a sub-multiple thereof. By suitable adjustments of the bias resistor, the plate voltage, and the variable capacitor,- I have discovered a narrow regionv of unusual operating characteristics located between the continuous discharge and the oscillatory condition at impulse frequency. In

grid for initiating a discharge of the plate capac- 3" itor through the gas tube as in the state of normal oscillation. Ihis discharge will not extinguish itself but will continue as a low current trickle discharge. In the case of the conventional adjustments, this discharge would -extinguish itself immediately. The low current discharge continues until the next impulse is applied to the grid. Probably because of the low 'current discharge, the second impulse exerts a '45v control action, which decreases the capacitor voltage which in turn extinguishes the discharge. This leaves the tube in its original condition in which the capacitor becomes charged through- The next impulse represents the beginning of a second cycle similar to the one just described.

In Flgl IIa the impulse whichv initiates the discharge is represented as K. The plate voltage is represented by the graph ALM of Figure IIb.

The low current discharge is represented by the horizontal portions of the graph N of Figure IIe.

The sharp rise and fall, or surge in the plate curthe limiter tube is adjusted so that the steady low current discharge in the gas tube will provide sufficient bias to cut off the plate current of the limiter tube, then surges above this value will be limited or cut off by the output tube. 'I'he resulting output characteristic of the network vis illustrated by Figure IId.

The saw-tooth wave form of Fig. IIb may be regulated by adjusting the resistance and capacitance of the plate circuit. The most convenient method for adjusting the circuit constants. is to connect a cathode ray oscillograph across the bias or protective resistor I3. The constants of the circuit are then varied until the proper wave form appears in the oscillograph. 'Ifhe adjustment may likewise be made by connecting the oscillograph to the output terminals 31-39 of the network. Other critical operating conditions also exist between the various regions of normal operation but use has been found only for the one described.

By way of example. I have found that circuits of this type may be operated by impulses at a 'rate of about 20,000 per second. The resistor I3 should have a resistance not greater than a value ten times the value normally required to protect the tube 9 against excessive current surges.- 'Ihe adjustment of the circuit constants is somewhat critical but the operation remains stable after the required adjustment has been made. The average impulse rate is preferably fairly constant. The individual impulses may have intervals giving 95% off time to95% 'on time of the trickle discharge.

The gas tube relay and circuit similar to Fig. I may beused to indicate every nthof a series of impulses. A suitable arrangement is shown in Fig. III. One of a pair of input terminals 4I, 43 is connected through a blocking capacitor 44 to the grid electrode 45 of a gas tube relay 41, of the RCA type 885, or the like. The: grid 45 is connected through a gri'dresistor46 and biasing battery 48 to the other input terminal 43. The cathode 49 of this tube is connected through a protective resistor 5I to the lower of the two input terminals. The plate 53 is connected to the positive terminal of a B battery 45 through an adjustable resistor 51. The plate 53 is also connected through a capacitor 59 to the negative terminal of the -B battery 55. the B battery is connected to the lower terminal of the-protective resistor 5I.

A second tube 6 I, preferably` similar to the rst tube, is connected in a similar circuit arrangement. The input of the second tube is connected to the protective resistor 5I of the first tube 41. A thirdtube 63, also by preference, similar to the first tube, is similarly connected across the protective resistor of the second tube. A pair of output terminals 65-61 are connected respectively to the cathode 69 and lower terminals of.

the several protective resistors. Biasing batteries 13 may be employed.

The operation of this circuit differs from Fig. I in that the critical region of operation is not used. The operating constants in this case are chosen to lie in the region of submultiple oscillatory dis- The negative terminal of discharge.

charge. I am aware that the operating condition of a submultiple discharge with. a protective resistor in the plate circuit is well known to those skilled in the art. The voltage across the feed resistor 51 in the plate circuit is saw-tooth in form. In many cases a sharp impulse form is desired.- I have discovered that the voltages across the protective resistor are a series of sharply defined impulses. By placing the protective resistor in the cathode lead, I have made these impulses conveniently available for any desired use. A

If the voltages applied to the grid are of short duration, the submultiple frequency in the output may be of the order of Vgth of the input frequency. While three stages are shown in Fig. III, one or more stages may be used.

The time constant of the capacitance and resistance of the plate circuit is adjusted to approximately ten times,-by way of example, that of the period of the input voltage, Fig. IVe. The plate voltage will vary in a saw-tooth pattern as shown in Fig. IVf. The voltage changes will correspond to plate current changes across the protective resistor similar to the impulses shown in Fig. IVg.

These voltage impulses occur at a rate which is toth that of the input voltages. The second tubelikewise reduces the rate of the impulses by picking out, for example, every th impulse by a. properly adjusted time constant plate circuit. Thus, the output of the second tube includes impulses at the rate of loth of the input to this found that the circuits described may be used as frequency dividers for ratio as high as 20 to 1 if the input voltage is a sharp uniform pulse. Frequency division of the type described is very useful Afor obtaining uniform low frequencyimpulses from a constant high frequency source. As an example, a constant 120 kilocycle source may be lstepped down to' 120 cycles for comparison with clocks, watches and the like. The system of Fig. I may be ein loyed, for example, to reproduce a telegraphic t nsmission, of a suitable type, from a series of i ulses marking the beginnings and endings of the telegraphic signals.

I claim as y invention:

1. In a devi e of the character described. a relay tube havi g grid, cathode, and plate electrodes, means r impressing input signals on said grid, a disch rge circuit associated with said cathode and pl te electrodes, a protective resistance serially nnected in said discharge circuit, and means for adjusting said circuit between the limits c! a steady discharge and an oscillatory discharge -within. 'which limits one input impulse impressed on vsaid grid starts a now of discharge current-which is not completely extinguished until the next input impulse cuts 'oil said 2. In a device of the character describe-d, a gaseous relay tube having grid, cathode, and plate electrodes, means for impressing input signals between said grid and cathode electrodes, a discharge circuit associated with said cathode and plate electrodes, a protective resistance joined to said cathode and serially connected in said discharge circuit, and means for adjusting said circuit within a region bounded by a steady disl. charge and an oscillatory discharge within which region one input impulse impressed on said grid starts a ow of discharge current'which is not completely extinguished until the next input impulse cuts off said discharge. l

3. In a device of the character described, a relay tube having grid, cathode. and plate electrodes, means for impressing input signals on said grid. a discharge circuit associated with said cathode and plate electrodes, a protective resistance serially connected in said discharge circuit, means for adjusting said circuit withina narrow region between a steady discharge and an oscillatory discharge within which region onev input impulse impressed on said grid starts a flow of discharge current which is not completely extinguished until thenext input impulse cuts oi said discharge, and means for impressing output voltages derived across said protective resist-'- including a subsequent electriccharge ofthe same sign as said first electric charge impressed on said grid for extinguishing said discharge current.

5. In a device of the character of claim 4, means for' deriving voltagesV from currents flowing in said protective resistance.

6. In a device of the character of claim 4, means for limiting voltages derived from currents ilowing in said protective resistance to predetermined values.

7. In a gas tube relay having grid. cathode and plate electrodes, a protective resistance, an input circuit including said grid and cathode, an

output circuit including said plate, protective resistance, and cathode, means for adjusting said circuits and said gastube operating parameter so that its operation lies in the region between asteady continuous discharge and an oscillatory discharge of substantially saw-tooth wave form,

successive charges of the same sign respectively start and stop said discharge current.

` 8. In a device of the character described, a relay tube having grid, cathode,l and plate elec-y trodes, means for impressing input signals on said grid, a discharge, circuit associated with said cathode and plate electrodes, a protective resistance serially connected in said discharge circuit, a source of current -for said discharge circuit, and means for adjusting said circuit within a narrow region limited by a steady discharge and an oscillatory discharge, and within which region one input impulse impressed on said grid starts a ow of discharge vcurrent whichis not completely extinguished until the next input impulse cuts oil said discharge.

9. In a device o1' the character described, a relay tube having grid, cathode, and plate velectrodes, means for impressing input`signals on said grid, a discharge circuit associated. with said cathode and plate electrodes, a protective resistance serially connected in-said discharge circuit, a source of current for said discharge cin'- cuit the negative terminal of said source being connected to said protective resistance, and means for adjusting said circuit within a region bounded by a steady discharge and an oscillatory. discharge at which adjustment one input impulse impressed on said grid starts a ow of discharge current which is not completely extinguished until the next input impulse cuts oiI said discharge.

DAVID G. C. LUCK. 

